#linuxcnc Logs

Aug 19 2019

#linuxcnc Calendar

01:35 AM Loetmichel: ouch... just arrived at the company... a 12 km drive... halfway thru it changed from "all normal" to "tornado alley"... tons of leaves and branches on the street, sawed in half trees in the ditches on both sides of the street, neighbor left has lost all roof tiles, neigbor on the right has no undamaged window and a blown out of the rails rolling truck gate on his company building... WTF?!?
01:40 AM CaptHindsight: how often do you get tornadoes there?
01:40 AM sensille: never ...
02:03 AM Loetmichel: sensille: dont know what you call it... if you have leaves on the walls up to second story and broken windows from blwon up gravel i call that "servere storm".. if that is a tornado or a hurricane: dont care.
02:05 AM sensille: "Orkan"
02:05 AM Loetmichel: yes
02:05 AM sensille: hurricane
02:06 AM CaptHindsight: hurricanes are many many Km across >100
02:06 AM CaptHindsight: tornadoes vary from a few m to a couple km
02:06 AM Deejay: moin
02:08 AM CaptHindsight: this tornado was the largest recorded 2.6m across, ~5km
02:08 AM CaptHindsight: https://youtu.be/KX8o2loAMhY?t=64
02:08 AM sensille: in my understanding: tornadoes rotate, hurricanes blow
02:11 AM CaptHindsight: hurricanes also rotate
02:12 AM CaptHindsight: https://www.youtube.com/watch?v=7shzR4HPbRw
02:13 AM sensille: yeah, on a large scale
02:13 AM CaptHindsight: there are also events like microbursts
02:13 AM sensille: but they don't suck stuff upwards
02:14 AM CaptHindsight: https://youtu.be/IIAEubQQ_Tk?t=139
02:15 AM CaptHindsight: https://youtu.be/dOSIjoZnHwI?t=184
02:40 AM * Loetmichel just went onto the roof: we have damage, too... a few broken windows and the roof ripped up. -> http://www.cyrom.org/palbum/main.php?g2_itemId=17478&g2_imageViewsIndex=1 but no comparsion har hard the neighbor got hit: http://www.cyrom.org/palbum/main.php?g2_itemId=17481&g2_imageViewsIndex=1
03:05 AM CaptHindsight: shows you which types of roofs are tougher
03:17 AM Loetmichel: CaptHindsight: judging from the damage: install solar panels... they are indestructible ;)
03:18 AM Loetmichel: i honestly forgot our roof was just truck canvas. was surprised wehen i went up today
03:27 AM pingufan: Hello.
03:27 AM pingufan: I am close to buying a new cnc spindle. It would be very helpful to know some setails, I have no experience with HF spindles.
03:28 AM pingufan: Does somebody have time for me?
03:30 AM pingufan: Currently I use a GravoGrapg VX machine. It has an ASYNC motor (220V AC) with a special speed regulator (with feedback). This motor runs the spindle through a 2-stage belt drive. So the motor is much lower, the spindle is ~ 12000-13000 rpm.
03:31 AM pingufan: The motor is ~ 150 Watts. So I estimate that 120 Watts will arrive on the spindle.
03:32 AM XXCoder: 150w spindle?
03:32 AM pingufan: Now it seems that the speed controller starts failing. It is >20yrs old, so no chance for a replacement.
03:32 AM XXCoder: siunds weak, mine is 400w and its pos
03:32 AM XXCoder: but same time, maybe its hp thing
03:32 AM XXCoder: ya 220v
03:32 AM Centurion_Dan: pingufan: I think your being overly generous for a multistage belt drive... expect to lose at least 10% of the power per belt stage
03:33 AM pingufan: My plan is to replace the entire head by a direct drive HF spindle, but I al very restricted in weight. (Then I have to lift the entire motor up/down.
03:35 AM pingufan: I found some well looking spindles at aliexpress and alibaba. One is 1.1 kg in weight, 24000rpm max, 300Watts. But it is for 39V and therefore the included MAC controller needs also a power supply. I don't have that space.
03:36 AM pingufan: Oh, it is 250 Watts only... https://www.aliexpress.com/item/32976290810.html?spm=a2g0o.cart.0.0.43823c00Jd2Sul
03:36 AM pingufan: But I'd prefer an ER11 chuck.
03:37 AM pingufan: But I am almost sure it will still be lots stronger and run more silent than my current machine.
03:37 AM XXCoder: this dont work? https://www.aliexpress.com/item/32864211347.html?spm=a2g0o.productlist.0.0.78583e43FGdY9
03:37 AM pingufan: DC motor usually is 12000 rpm only.
03:38 AM XXCoder: can vary speed but loses torque yeah
03:38 AM pingufan: Tada, yes, 12000rpm as described below. I'd like a bit higher speed. I often use 1mm cutters.
03:39 AM XXCoder: one you linked to is e8 unfortunately
03:39 AM XXCoder: er8
03:39 AM pingufan: A brushless spindle is usually a synchronous motor, so it doen't change the speed on varying load.
03:40 AM pingufan: I know, it is ER8. But I already have a full set of ER11 chucks, therefore I'd prefer ER11.
03:40 AM pingufan: A DC motor will need a feedback loop to keep rpm constant.
03:41 AM XXCoder: yep thats why I added magnet sensor and magnets to my spindle in order to add that
03:41 AM XXCoder: since my machines for wood dont need more complex spindle than that
03:42 AM pingufan: What I am unsure about is: The manufacturer of a different spindle told me they are constant torque.
03:43 AM XXCoder: dc very much not, one you linked to might be
03:43 AM pingufan: I often machine plastic, wood, PCBs, ..., aluminium, brass.
03:44 AM pingufan: DC motors for sure are very load sensitive.
03:44 AM pingufan: I do not want to pay hindreds of USD and finally have it even worser.
03:45 AM pingufan: Therefore I ask.
03:45 AM XXCoder: yeah not sure about that one, hopefully someone can answer
03:45 AM XXCoder: chat here tend to get more busy in hour or 2
03:47 AM pingufan: With ER11, most spindles start at 500 or 800 Watts. This babies weigh 3.0 kg or more. Too much for my little mill.